SYNTHESIS OF PHENYLDIAZENIDO, PHENYLHYDRAZIDO AND DIORGANOHYDRAZIDO COMPLEXES OF MOLYBDENUM AND TUNGSTEN AND THEIR REACTIONS WITH ACIDS - ACOMPARISON WITH ANALOGOUS UNSUBSTITUTED HYDRAZIDO (NNH2) COMPLEXES - THE CRYSTAL-STRUCTURE OF [WCL2(NN(H)PH)(PME(2)PH)(3)]

The phenyldiazenido complexes [MCl(NNPh)(PMe(2)Ph)(4)] (M = Mo, W) and phenyl- and diorganohydrazido(2-) complexes [WCl2(NN(H)Ph)(PMe(2)Ph)( 3)], [MCl(2) (NNRR')(PMe(2)Ph)(3)] (M = Mo, W; R = R' = Me, R = R' = P h; M = W, R = Me, R' = Ph), [MCl(2)(NNPh(2))(dppe)(PMe(2)Ph)] (M = Mo, W; dppe = Ph(2)PCH(2)CH(2)PPh(2)), [MCl(NNPh(2))(dppe)(2)]Cl (M = Mo, W), and [WCl(NN(Me)Ph)(dppe)(2)]Cl were synthesized, characterized an d their reactions with acids studied. These complexes were prepared in a series of reactions starting with WCl6 or (MoCl5)(2) involving (i) introduction of the organohydrazido(2-) group (NNRR') using the corres ponding hydrazine (R = R' = Me) or hydrazine hydrochloride (R = R' = P h; R = Ph, R' = H or Me), and (ii) incorporation of phosphine ligands under reducing conditions. The particular product formed in the last s tep depended upon the reduction time. In almost all cases reaction of the complexes with acid (1 M HCl in Et(2)O or H2SO4 in MeOH) resulted in the formation of some amine and a correspondingly smaller amount of ammonia. For example, the yields of aniline and ammonia when [MCl(NNP h)(PMe(2)Ph)(4)]Cl reacted with H2SO4 in MeOH were ca 0.2 mol and ca 0 .1 mol per mol of W, and 0.70 mol and 0.65 mol per mol of Mo, respecti vely. A comparison of acid reactions of organodiazenido and organohydr azido(2-) is made with those of unsubstituted hydrazido(2-) complexes prepared from coordinated dinitrogen. The crystal structure of reddish -brown [WCl2(NN(H)Ph)(PMe(2)Ph)(3)] revealed a distorted octahedral co mplex in which the hydrazido(2-) moiety is tl ans to a chlorine atom a nd the hydrazido(2-) phenyl group is coplanar with the plane containin g W, N, N and C(Ph) atoms. The second chlorine atom, cis to the hydraz ido(2-) ligand, has a close intermolecular contact (2.62 Angstrom) wit h the hydrazido(2-) hydrogen atom of a neighbouring molecule and close intramolecular contact (2.76 Angstrom) with the endo o-phenyl hydroge n atom of the hydrazido(2-) ligand. Comparison of structural data with those for [WCl2(NNR(2))(PMe(2)Ph)(3)] (R(2) = Me(2) or Ph(2)) indicat es significant differences in W-N(1) and W-Cl(trans) distances between the dimethyl-, and the phenyl- and diphenylhydrazido(2-) complexes, r espectively.